Composition effects on photooxidative membrane destabilization by TiO 2 nanoparticles.

Autor: Malekkhaiat Häffner S; Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark. Electronic address: saramalekkhaiat@gmail.com., Parra-Ortiz E; Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark., Skoda MWA; ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell, Oxfordshire OX11 OQX, UK., Saerbeck T; Institut Laue-Langevin, CS 20156, 38042 Grenoble Cedex 9, France., Browning KL; Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark., Malmsten M; Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark; Department of Physical Chemistry 1, University of Lund, SE-22100 Lund, Sweden.
Jazyk: angličtina
Zdroj: Journal of colloid and interface science [J Colloid Interface Sci] 2021 Feb 15; Vol. 584, pp. 19-33. Date of Electronic Publication: 2020 Sep 22.
DOI: 10.1016/j.jcis.2020.09.046
Abstrakt: Membrane interactions and photooxidative membrane destabilization of titanium dioxide (TiO 2 ) nanoparticles were investigated, focusing on the effects of membrane composition, notably phospholipid headgroup charge and presence of cholesterol. For this, we employed a battery of state-of-the-art methods for studies of bilayers formed by zwitterionic palmitoyloleoylphosphatidylcholine (POPC) containing also polyunsaturated palmitoylarachidonoylphosphocholine (PAPC), as well as its mixtures with anionic palmitoyloleoylphosphatidylglycerol (POPG) and cholesterol. It was found that the TiO 2 nanoparticles display close to zero charge at pH 7.4, resulting in aggregation. At pH 3.4, in contrast, the 6 nm TiO 2 nanoparticles are well dispersed due to a strongly positive ζ-potential. Mirroring this pH dependence, TiO 2 nanoparticles were observed to bind to negatively charged lipid bilayers at pH 3.4, but much less so at pH 7.4. While nanoparticle binding has some destabilizing effect alone, illumination with ultraviolet (UV) light accentuates membrane destabilization, a result of oxidative stress caused by generated reactive oxygen species (ROS). Neutron reflectivity (NR), quartz crystal microbalance (QCM), and small-angle X-ray scattering (SAXS) results all demonstrate that membrane composition strongly influences membrane interactions and photooxidative destabilization of lipid bilayers. In particular, the presence of anionic POPG makes the bilayers more sensitive to oxidative destabilization, whereas a stabilizing effect was observed in the presence of cholesterol. Also, structural aspects of peroxidation were found to depend strongly on membrane composition, notably the presence of anionic phospholipids. The results show that membrane interactions and UV-induced ROS generation act in concert and need to be considered together to understand effects of lipid membrane composition on UV-triggered oxidative destabilization by TiO 2 nanoparticles, e.g., in the context of oxidative damage of bacteria and cells.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2020 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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